This application proposes a Clinical Research Center (CRC) dedicated to the study of suicide and suicidal behavior. There are approximately 30,000 suicides per year in the United States and ten times that number of suicide attempts. SEveral research priorities must be addressed so that we can respond to this major health problem. Current predictors of suicide risk have high sensitivity but inadequate specificity. In this regard recently identify biological correlates of more lethal suicidal behavior have created hope that more specific predictors of suicide risk may be found. To demonstrate by controlled studies that treatment interventions can reduce suicide risk requires such specific predictors in order to identify a high risk group. A multidisciplinary approach is necessary to develop a predictive model for suicidal behavior because potential factors are demographic, social, developmental, psychiatric, genetic and biological. Cross sectional identification of risk factors and ultimately prospective testing requires high versus low risk populations such that the frequency of suicidal behavior is sufficient to test these risk populations such that the frequency of suicidal behavior is sufficient to test these risk factors. This suicide research approach requires a CRC structure to permit an integrated approach to a multidimensional problem. The initial phase of proposed activity will involve establishment of a working CRC structure and will concentrate on cross sectional identification of risk factors. Four methodological advances will distinguish this proposal from previous studies. First, an integrated series of multi-disciplinary measures (social, demographic, psychological, psychiatric and biological) that evaluate hypothesized risk factors for suicidal behavior will be carried out on the same patients population including affective disorders, schizophrenia and personality disorders to establish which risk factors are disease-specific versus suicide-specific and to determine disease-suicide risk interactions. Third, we will initiate limited follow-up of high-risk populations (attempters) and controls (nonattempters). Such a prospective study is needed to test promising predictors suggested by the results of the cross-sectional study. Fourth, results of these clinical studies together with results of a concurrent psychological and biological study of completed suicides will be employed to generate an integrated model of suicidal behavior.